Polyarylate refers to a linear polyester resin belonging to the aromatic group and is prepared by poly-condensing an aromatic diol and an aromatic dicarboxylic acid.
Such a polyarylate resin can have several molecular formulas, depending upon the source material. Polyarylate resin comprising structural units of Formula 2 described below that is reacted with bisphenol A as a bivalent phenol and terephthalic acid or isophthalic acid as a dicarboxylic acid by a polycondensation is an exemplary product.

Recently, certain bivalent phenol compounds having a bulky substitute group are sometimes utilized to raise a transition temperature of separation (Tg). For example, the compound having the structure of Formula 3 can be adopted.

The polyarylate resin of Formula 2 is known in the art as an engineering plastic. In practice, the polyarylate can be widely used in the field of electric and electronic appliance part: for a switch, a socket, parts of a microwave, a relay case and a plate since the polymer. In mechanical products, it can be widely used as material or a packaging matter to prepare various products, such as inner or and outer parts of watch, parts of optical machine, parts of heating device including a contact breaker of gas, lenses for a housing or an automobile, overall housing products and instrument boards.
In reference, the method for preparing polyarylate resin, wherein n-butylbenzyl ammonium chloride is used as a cationic catalyst to prepare high molecular weight in the interfacial polymerization, has been disclosed in Japanese Patent Laid-open No. 43670/1993. However, the polyarylate prepared above is liable to leave catalysts and salts in the organic phase of polymer solution after finishing the interfacial polymerization, because of a high lipophilic property of the catalyst. The resulting polyarylate resin may include a lot of residual catalysts and salts so as to reduce the physical property of polyarylate.
Also, the method for preparing 1,6-diaza[4,4]spirolactam compounds substituted by hydroxyaryl, has been demonstrated in U.S. Pat. No. 4,992,526. In this technique, the copolymer reacting an aromatic dicarboxylic acid halogen compound and a spirolactam compound substituted for hydroxyaryl and/or the tripolymer further added by a bivalent phenol compound, are prepared by using a cationic catalyst for the phase transition. This invention aims to provide a process for preparing a spirolactam compound, as expressed in the title. Within the scope of the invention, an aromatic dicarboxylic acid halogen compound and a bivalent phenol compound are included, focusing on the spirolactam compound. However, there are several disadvantages as follows. In technical aspects, the cationic catalyst for the phase transition increases Haze of film, if remained in the final resin (typically, 0.5% of Haze increases, if 0.5 wt % of catalyst remains); reduces the thermo-stability of polymer; needs to increase the frequency of cleaning; and the like. Even in economical aspects, the catalyst should be beyond a predetermined amount to synthesize a high molecular weight product as well as is very expensive.